A spokesman with the Department of Licensing and Regulatory Affairs, the agency behind the shutdowns, didn’t identify the types of businesses targeted or how they were identified, the Detroit Free Press reported.

But the letters suggest they failed to apply for state business licenses by the Feb. 15 deadline set under emergency program rules passed late last year.

The Free Press also noted most were probably dispensaries.

The cease-and-desist letters say that the emergency rules permit “an applicant for a state operating license to temporarily operate a proposed marijuana facility under certain conditions,” according to the newspaper.

The letters also say that “to comply with this rule, a temporarily operating facility must have applied for a state operating license by February 15. … A person that does not comply with this rule shall cease and desist operation of a proposed marijuana facility.”

The newspaper reported that the letters warn that owners who don’t shut down jeopardize their chances of getting a state license and could be referred to law enforcement officials.

State officials delivered the letters to the 40 dispensaries in person but did not confiscate any products.

Michigan began accepting business license applications in December but probably won’t award licenses until April, according to the Free Press.